U.S. patent number 5,296,843 [Application Number 07/677,643] was granted by the patent office on 1994-03-22 for fluid or vapor diagnostic device.
This patent grant is currently assigned to SD Laboratories, Inc.. Invention is credited to Emil W. Ciurczak, Scott D. Wohlstein.
United States Patent |
5,296,843 |
Wohlstein , et al. |
March 22, 1994 |
Fluid or vapor diagnostic device
Abstract
A device is provided which passes light of preselected
wavelengths through a fluid or vapor to be tested. The light is
detected after it has passed through the fluid or vapor. Upon
detection, a voltage is created which is proportional in amplitude
to the detected light strength for each wavelength of light. These
voltages are compared to produce a ratio which represents the
condition of the fluid or vapor which is tested. When the ratio is
outside of preselected boundaries, control signals are generated
which may trigger alarms or otherwise respond to the condition.
Inventors: |
Wohlstein; Scott D. (Convent
Station, NJ), Ciurczak; Emil W. (Morristown, NJ) |
Assignee: |
SD Laboratories, Inc. (Convent
Station, NJ)
|
Family
ID: |
24719563 |
Appl.
No.: |
07/677,643 |
Filed: |
March 28, 1991 |
Current U.S.
Class: |
340/603; 250/573;
250/575; 340/438; 356/320; 356/436; 356/70 |
Current CPC
Class: |
G01N
21/3151 (20130101) |
Current International
Class: |
G01N
21/31 (20060101); G08B 021/00 () |
Field of
Search: |
;340/603,619,438
;250/573,575 ;356/70,319,320,436 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hofsass; Jeffrey
Attorney, Agent or Firm: Kinghorn; Curtis D.
Claims
What I claim is:
1. A non-destructive diagnostic device for continuously testing
fluid or vapor contained in a fluid or vapor reservoir
comprising:
a) at least two light sources, each of said light sources emitting
light at a different preselected wavelength;
b) means for directing light from each of said light sources
through the fluid or vapor;
c) means for receiving light from each of said light sources after
it has been directed through the fluid or vapor,
d) means for positioning said means for directing light and said
means for receiving light in the fluid or vapor reservoir, said
means for receiving light separated from said means for directing
light by a distance, thereby forming a gap through which the fluid
or vapor may pass;
e) means, connected to said means for receiving light, for
determining the absolute intensity of light from each of said light
sources after the light has been directed through the fluid or
vapor in the reservoir and passed to said means for determining
through said means for receiving;
f) means for determining the ratio of absolute intensity of light
from each of said light sources after the light has been directed
through the fluid or vapor;
g) means, responsive to said means for determining, for creating a
control signal indicating that said ratio is outside of a
preselected limit; and,
h) means, responsive to said control signal, for communicating that
said ratio is outside of said preselected limit.
2. The device of claim 1, wherein said light sources are chosen
from a group consisting of photodiodes, light emitting diodes,
laser diodes, SRLEDs, lasers, and monochromatic incandescent light
bulbs.
3. The device of claim 1, wherein said light sources comprise means
for creating monochromic light.
4. The device of claim 1 wherein said means for directing light
comprises input fiber optic cables receiving light from respective
said light sources at one end and directing said light through the
fluid or vapor at the other end.
5. The device of claim 1 wherein said means for receiving light
comprises output fiber optic cables, said output fiber optic cables
each receiving at one end light directed through the fluid or vapor
from said respective means for directing light, and passing said
light to respective said means for determining at the other end of
said output fiber optic cables.
6. The device of claim 1 further comprising a probe, said probe
being insertable into the fluid or vapor to be tested, said means
for directing light including respective fiber optic input cables
connecting each of said light sources with the fluid or vapor to be
tested, said means for receiving light also including respective
fiber optic output cables extending from the fluid or vapor to be
tested to respective said means for determining the absolute
intensity, said input and output cables extending into and out of,
respectively, said probe, respective said input and output cables
corresponding to each of said light sources, respective said input
and output cables being separated from each other within said probe
thereby forming said gap, each of said gaps in contact with the
fluid or vapor whereby fluid or vapor to be tested may move though
each of said gaps between said input and output cables so that
light from said each of said respective light sources travels
through its respective said input cable, through its respective
said gap, and through its respective said output cable before
impinging on respective said means for determining the absolute
intensity.
7. The device of claim 1, wherein said means for determining the
absolute intensity of light from each of said light sources after
it has been directed through said fluid comprises a
spectrometer.
8. The device of claim 7 wherein said spectrometer includes
detectors for detecting the light chosen from a group consisting of
cadmium sulfide (Cds) detectors and Lead Sulfide-Lead Selenium
(pbS/PbSe) detectors.
9. The device of claim 1, wherein said means for determining the
ratio of absolute intensity of light comprises an analog
divider.
10. The device of claim 1, wherein said means for creating control
signals includes a central processing unit electronically connected
to said means for determining the ratio of absolute intensity of
light, said central processing unit programmed to generate a
control signal when said ratio of absolute intensity of light is
determined by said central processing unit to be outside of a range
of operating parameters preprogrammed into said central processing
unit.
11. The device of claim 1 further comprising means for modulating
said light sources.
12. The device of claim 11 wherein said means for modulating said
light sources comprises means for alternately pulsing respective
said light sources and simultaneously activating the corresponding
said means for determining the absolute intensity of light so that
light from one light source that is diffracted by the fluid or
vapor will impinge on an inactive means for determining the
absolute intensity of light corresponding to an inactive said light
source.
13. The device of claim 1 wherein said gap has a width of between 1
and 20 millimeters when a fluid is passed through said gap and a
width of between 10 and 20 centimeters when a vapor is passed
through said gap.
14. A non-destructive diagnostic device for continuously testing
fluid or vapor contained in a fluid or vapor reservoir
comprising:
a) at least two light sources, each of said light sources emitting
light at a different preselected wavelength;
b) means for directing light from each of said light sources
through the fluid or vapor comprising respective input fiber optic
cables, said input fiber optic cables receiving light from said
light sources at a first end and directing the light through the
fluid or vapor at a respective second end;
c) means for receiving light from each of said light sources after
it has been directed through the fluid or vapor comprising
respective output fiber optic cables, each having a first and
15. The device of claim 14, wherein said means for creating control
signals includes a central processing unit electronically connected
to said means for determining the ratio of absolute intensity of
light, said central processing unit programmed to generate a
control signal when said ratio of absolute intensity of light is
determined by said central processing unit to be outside of a range
of operating parameters preprogrammed into said central processing
unit.
16. The device of claim 14 further comprising a probe, said probe
being insertable into the fluid or vapor to be tested, said probe
enclosing respective said second ends of said input fiber optic
cables and said first end of said output fiber optic cables, said
second end of said input fiber optic cables and said first end of
said output fiber optic cables being separated thereby forming said
gap through which the fluid or vapor may pass whereby fluid or
vapor to be tested may move through each of said gaps between said
input and output cables so that light from each of said respective
light sources travels through its respective said input cable,
through its respective said gap, and through its respective said
output cable before impinging on respective said spectrometer.
17. A non-destructive diagnostic device for continuously testing
fluid or vapor comprising:
a) at least two photo diodes, each of said photo diodes emitting
light at a different preselected wavelength;
b) means for directing light from each of said photo diodes through
the fluid or vapor comprising respective input fiber optic cables,
said input fiber optic cables receiving light from respective said
light sources at a first end and directing the light through the
fluid or vapor at a respective second end;
c) means for receiving light from each of said photo diodes after
it has been directed through the fluid or vapor comprising
respective output fiber optic cables, each having a first and a
second end, respective said output fiber optic cables each
receiving light directed through the fluid or vapor from respective
said input fiber optic cables at said first end, respective said
input fiber optic cables separated from respective said output
fiber optic cables by a distance, thereby forming a gap through
which the fluid or vapor may pass, said gap having a width of
between 1 and 20 millimeters when a fluid is passed through said
gap and a width of between 10 and 20 centimeters when a vapor is
passed through said gap;
d) means, connected to said second end of respective said output
fiber optic cables, for determining the absolute intensity of light
from each of said photo diodes after the light has been directed
through the fluid or vapor, said means for determining comprising a
spectrometer, whereby each of said light sources has a
corresponding means for directing light and a means for receiving
light;
e) means for determining the ratio of absolute intensity of light
from each of said photo diodes after the light has been directed
through the fluid or vapor, comprising an analog divider;
means, responsive to said means for determining, for creating
control signals indicating that said ratios are outside of
preselected limits;
g) means, responsive to said control signals, for communicating
that said ratios are outside of preselected limits; and
h) a probe, said probe being insertable into the fluid or vapor to
be tested, said probe enclosing respective said second ends of said
input fiber optic cables and said first end of said output fiber
optic cables, said second end of said input fiber optic cables and
said first end of said output fiber optic cables being separated
thereby forming said gap through which the fluid or vapor may pass
whereby fluid or vapor to be tested may move through each of said
gaps between said input and output cables so that light from each
of said respective light sources travels through its respective
said input cable, through its respective said gap, and through its
respective said output cable before impinging on respective said
spectrometer.
18. A non-destructive diagnostic device for continuously testing
fluid or vapor comprising:
a) at least two light sources, each of said light sources emitting
light at a different preselected wavelength;
b) means for directing light from each of said light sources
through the fluid or vapor;
c) means for receiving light from each of said light sources after
it has been directed through the fluid or vapor, said means for
receiving light separated from said means for directing light by a
distance, thereby forming a gap through which the fluid or vapor
may pass;
d) means, connected to said means for receiving light, for
determining the absolute intensity of light from each of said light
sources after is has been directed through the fluid of vapor and
passed to said means for determining through said means for
receiving, whereby each of said light sources has a corresponding
means for directing light, means for receiving light, and means for
determining the absolute intensity of light;
e) means for determining the ratio of absolute intensity of light
from each of said light sources after the light has been directed
through the fluid or vapor;
f) means, responsive to said means for determining, for creating
control signal indicating that said ratio is outside of a
preselected limit;
g) means, responsive to said control signals, for communicting that
said ratio is outside of said preselected limit; and,
h) a probe, said probe being insertable into the fluid or vapor to
be tested, said means for directing light including respective
fiber optic input cables connecting each of said light sources with
the fluid or vapor to be tested, said means for receiving light
also including respective fiber optic output cables extending from
the fluid or vapor to be tested to respective said means for
determining the absolute intensity, said input and output cables
extending into and out of, respectively, said probe, respective
said input and output cables corresponding to each of said light
sources, respective said input and output cables being separated
from each other within said probe thereby forming said gap, each of
said gaps in contact with the fluid or vapor whereby fluid or vapor
to be tested may move through each of said gaps between said input
and output cables so that ligh from each of said respective light
sources travels through its respective said input cable, through
its respective said gap, and through its respective said output
cable before impining on respective said means for determining the
absolute intensity.
19. The device of claim 18 wherein said probe is adapted to be
hand-held and manually inserted into the fluid or vapor to be
tested.
20. The device of claim 18 wherein said probe comprises:
a) a connector, through which said fiber optic input cables enter
said probe and said fiber optic output cables exit said probe;
b) a bulk head, attached to said connector, for positioning said
fiber optic input and output cables; and
c) a wall placed between respective pairs of fiber optic input and
fiber optic output cables so that light emitted from one of said
fiber optic input cables is inhibited from being diffracted into
another non-corresponding fiber optic output cable.
21. The device of claim 20 wherein said probe further comprises a
screen surrounding said fiber optic input and output cables and
said wall so that said gap between said fiber optic input and
output cables is shielded from debris passing into said gap.
22. A method for non-destructively and continuously testing fluids
or vapors for contaminants, the fluid or vapor contained in a fluid
or vapor reservoir, the fluid or vapor taken from a group
consisting of oil based lubricants, hydraulic oils, brake fluids,
transmission fluids, coolant or radiator fluids, organic, carbon
based fuel vapors, and organic, carbon based solvent vapors,
comprising the steps of:
a) passing light of at least two different wavelengths through the
reservoir of fluids or vapors;
b) detecting the light of the different wavelengths after the light
has passed through the reservoir;
c) determining the absolute intesntiy of the light of the different
wavelengths after the light has been detected;
d) determining the ratio of the determined absolute intensities of
the light; and,
e) comparing the determined ratio to a preestablished ratio of
absolute intensities of the light to determine whether the
determined ratio indicates that the condition of the fluid or vapor
is outside acceptable values.
23. A non-destructive diagnostic device for continuously testing
fluid or vapor comprising:
a) at least two light sources, each of said light sources emitting
light at a different preselected wavelength;
b) means for directing light from each of said light sources
through the fluid or vapor;
c) means for receiving light from each of said light sources after
it has been directed through the fluid or vapor, said means for
receiving light separated from said means for directing light by a
distance, thereby forming a gap through which the fluid or vapor
may pass;
d) means, connected to said means for receiving light, for
determining the absolute intensity of light from each of said light
sources after it has been directed through the fluid of vapor and
passed to said means for determining through said means for
receiving, whereby each of said light sources has a corresponding
means for directing light, means for receiving light, and means for
determining the absolute intensity of light;
e) means for determining the ratio of absolute intensity of light
from each of said light sources after the light has been directed
through the fluid or vapor;
f) means, responsive to said means for determining, for creating
control signals indicating that said ratio is outside of a
preselected limit;
g) means, responsive to said control signals, for communicating
that said ratio is outside of said preselected limit; and,
h) means for modulating said light sources comprising means for
alternately pulsing respective said light sources and
simultaneously activating the corresponding said means for
determining the absolute intensity of light so that light from one
light source that is diffracted by the fluid or vapor will impinge
on an inactive means for determining the absolute intensity of
light corresponding to an inactive said light source.
24. A non-destructive diagnostic device for continuously testing
fluid or vapor comprising:
a) at least two light sources, each of said light sources emitting
light at a different preselected wavelength;
b) means for directing light from each of said light sources
through the fluid or vapor comprising respective input fiber optic
cables, said input fiber optic cables receiving light from said
light sources at a first end and directing the light through the
fluid or vapor at a respective second end;
c) means for receiving light from each of said light sources after
it has been directed through the fluid or vapor comprising
respective output fiber optic cables, each having a first and a
second end, respective said output fiber optic cables each
receiving light directed through the fluid or vapor from respective
said input fiber optic cables at said first end, respective said
input fiber optic cables separated from respective said output
fiber optic cables by a distance thereby forming a gap through
which the fluid or vapor may pass;
d) means, connected to said second end of respective said output
fiber optic cables, for determining the absolute intensity of light
from each of said light sources after the light has been directed
through the fluid of vapor, said means for determining comprising a
spectrometer, whereby each of said light sources has a
corresponding means for directing light and a means for receiving
light;
e) means for determining the ratio of absolute intensity of light
from each of said light sources after the light has been directed
through the fluid or vapor, comprising an analog divider;
f) means, responsive to said means for determining, for creating
control signals indicating that said ratios are outside of a
preselected limits;
g) means, responsive to said control signals, for communicating
that said ratios are outside of said preselected limits; and,
h) a probe, said probe being insertable into the fluid for vapor to
be tested, said probe enclosing respective said send ends of said
input fiber optic cables and said first end of said output fiber
optic cables, said second end of said input fiber optic cables and
said first end of said output fiber optic cables being separated
thereby forming said gap through which the fluid or vapor may pass
whereby fluid or vapor to be tested may move through each of said
gaps between said input and output cables so that light from each
of said respective light sources travels through its respective
said input cable, through its respective said gap, and through its
respective said output cable before impinging on respective said
spectrometer.
25. A non-destructive diagnostic device for continuously testing
fluids or vapors for contaminants, said fluids or vapors contained
in a fluid or vapor reservoir, the fluid or vapor taken from a
group consisting of oil based lubricants, hydraulic oils, brake
fluids, transmission fluids, coolant or radiator fluids, organic,
carbon based fuel vapors, and organic carbon based solvent vapors,
comprising:
a) means for passing light of at least two different wavelengths
through the reservoir of fluids or vapors;
b) means for detecting the light of the different wavelengths after
the light has passed through the reservoir;
c) means for positioning said means for passing light and said
means for detecting the light in the reservoir, said means for
receiving light separated from said means for directing light by a
distance, thereby forming a gap through which the fluid or vapor
may pass;
d) means for determining the absolute intensity of the light of the
different wavelengths after the light has been detected;
e) means for determining the ratio of the determined absolute
intensities of the light; and,
f) means for comparing the determined ratio to a preestablished
ratio of absolute intensities of light to determine whether the
determined ratio indicates that the condition of the sample is
outside acceptable values;
wherein said device operates according to the following steps:
g) passing light of at least two different wavelengths, from said
means for passing light, through fluid or vapor;
h) detecting the light of the different wavelengths, by said means
for detecting light, after the light has passed through the fluid
or vapor; p1 i) determining the absolute intensity of the light of
the different wavelengths, by said means for determining the
absolute intensity of the light, after the light has been detected
by said means for detecting;
j) determining the ratio of the determined absolute intensities of
the light by said means for determining the ratio; and,
k) comparing the determined ratio, by said means for determining,
to a preestablished ratio of absolute intensities of light to
determine whether the determined ratio indicates that the condition
of the sample is outside acceptable values.
26. A non-destructive diagnostic device for continuously testing
oil based lubricants contained in a reservoir, comprising:
a) means for passing light of at least two different wavelengths
through the reservoir of oil based lubricants, said wavelengths
including 450 nanometers and 550 nanometers;
b) means for detecting the light of the different wavelengths after
the light has passed through the oil in the reservoir;
c) means for positioning said mean for passing light and said means
for detecting the light in the reservoir, said means for detecting
the light separated from said means for passing light by a
distance, thereby forming a gap through which the oil based
lubricant may pass;
d) means for determining the absolute intensity of the light of the
different wavelengths after the light has been detected;
e) means for determining the ratio of the determined absolute
intensities of the light; and,
f) means for comparing the determined ratio to a preestablished
ratio of absolute intensities of light to determine whether the
determined ratio indicates that the condition of the sample is
outside acceptable values.
Description
FIELD OF THE INVENTION
The instant invention relates to a fluid or vapor diagnostic device
and more particularly to a device which non-destructively
determines the quality of a fluid or vapor tested by passing light
of different wavelengths through the fluid or vapor and then
comparing the ratio of the resulting detected light strength to a
predetermined ratio indicating whether the fluid's or vapor's
operating parameters are within acceptable limits.
BACKGROUND OF THE INVENTION
It has been found that when many fluids are exposed to a variety of
environmental conditions, their physical properties change. These
changes occur primarily in two areas. The chemical composition of
the fluid itself may be changed through the application of heat,
pressure, chemical reactions with other fluids, or air-oxidation.
In addition, the fluid may be contaminated by other fluids,
contaminants or particulate matter from other sources, which,
although not chemically combining with the fluid, affects the
fluid's ability to function as it was intended, which function is
best accomplished by a pure fluid.
Exemplary of such a fluid susceptible to both of these changes is
lubricating motor oil used in an internal combustion engine. A pure
motor oil is ideally suited for providing lubrication within the
internal combustion engine. However, due to the high temperature
necessarily present in such engines, breakdown of the molecular
structure of the motor oil takes place with resulting loss of
lubricating ability. The remnants of the broken down motor oil
molecules remain in the motor oil as contaminants. In addition,
other contaminants such as carbon deposits and fine metal particles
which result from the operation of the engine are also introduced
into the motor oil thereby contaminating it. Other contaminants are
introduced into the motor oil such as water or anti-freeze from the
engine cooling system. Dust particles, introduced into the engine
with the air through the carburization system, are blown past
compression and oil rings into the engine crank case from the
combustion chamber during the compression stroke of the
pistons.
Given time, the breakdown of pure motor oil and the introduction of
contaminants into the motor oil renders the motor oil unable to
effectively perform its job of lubricating the engine parts. When
this occurs, the used motor oil should be replaced with new motor
oil. The amount of time it takes for motor oil to reach this
condition depends on a variety of factors including the strain put
on the engine, the adequacy of cooling measures related to the
engine, and external environment of the engine during
operation.
Many fluids have additives added to them to enhance their inherent
capabilities. These additives result in variant chemical and light
absorbing properties. Examples of such chemicals are the various
types of fuel enhancers used in the automotive fuel industry. For
example, the introduction of ethanol, a common additive in many
fuels, radically changes in a predictable way the overall light
absorption properties of the resultant ethanol gasoline
mixture.
The instant invention was designed to detect both when a fluid,
either by breakdown or by contamination, has moved outside of an
acceptable range of operating parameters, and also when the
presence of certain additives are present in the tested fluid.
In researching these two problems, it was discovered that the light
absorbing properties of a fluid is altered by the breakdown of the
fluid itself, or by the introduction of contaminants or additives
into the fluid. It was also discovered that breakdown or
contamination of the fluid affects the light absorbing
characteristics of the fluid by different amounts for different
wavelengths of light. In particular, it was found that a ratio
established by passing light of various wavelengths through the
fluid to be tested and then detecting and comparing the strength of
the light after passing through the fluid indicates the condition
of the fluid related to the above mentioned detrimental
characteristics. In particular, it was found that when the ratio
for the preselected wavelengths reaches a certain ratio, the fluid
is no longer within acceptable standards set for the fluid. With
this in mind, the instant invention was motivated.
Because the change in fluid takes place within the environment
where the fluid is found and because change in the fluid is a
continuous process, the fluid should be tested continuously while
it is being used in order to immediately detect detrimental
changes. In this context, it is preferable to non-destructively,
continuously test the fluid so that the testing process itself does
not contribute to the breakdown and contamination problems of the
fluid. Therefore, the light of various wavelengths should be
introduced to the fluid in such a way that it can continuously and
non-destructively interact with the fluid while helping to
determine the condition of the fluid.
SUMMARY OF THE INVENTION
Light of preselected wavelengths is passed through a fluid to be
tested. The light is detected after passing through the fluid.
Thereafter, a voltage is created for each wavelength of light,
proportional in amplitude to the detected light strength of each
wavelength. These proportional voltages are compared to produce a
ratio which represents the condition of the fluid. When the ratio
is outside a preset acceptable limit, control signals, which may
trigger alarms or other warning devices, are triggered.
The light of the selected wavelengths is created preferable by
appropriate photodiodes. The light is introduced into the fluid to
be tested by transmitting the light of the various frequencies
through respective fiber optic cables into a reservoir of the
fluid. There the light is emitted across a gap through which the
fluid may travel. The emitted light is then received through a
corresponding fiber optic cable on the other side of the gap. The
received light is transmitted through a fiber optic cable out of
the reservoir where its strength may be determined.
The signal strength of the light received across the gap is
determined by having the light impinge on a detector which produces
a voltage output proportional to the impinging light strength. The
resulting electronic analog signal may be processed to amplify it
and filter noise present with the signal. Thereafter, the
electronic signals corresponding to the detected light strengths
from the different wavelengths are electronically combined to from
a ratio. This ratio has been found to represent the quality of the
fluid that is being tested.
The ratio is analyzed to determine whether it lies within
preselected boundaries representing acceptable qualities of the
fluid. If the ratio is found to be outside of these boundaries,
control signals are generated to draw attention to the unacceptable
quality of the fluid.
In the preferred embodiment, a probe containing the light emitting
and receiving fibers, as well as the gap between them, is mounted
in the wall of a reservoir of a fluid to be tested. The light
creating devices, the light detectors, ratio determining and
analyzing circuitry, control signal generator circuitry, and alarm
means are all located outside the fluid reservoir.
In an alternate embodiment, a handheld unit having a probe
comprising respective input and output fiber optics separated by a
gap is provided. The probe may be immersed into a selected fluid
for testing. In this embodiment, the operation of the device is
exactly the same as that described above except that the gap and
fiber optic cords are not continuously present within the fluid
reservoir to be tested, but are instead inserted into the fluid at
the discretion of the user.
It is an object of the invention to provide a device for
non-destructive testing of fluids and vapors in real time in the
environment where the fluids and vapors are found under work
conditions.
It is another object of the invention to provide a device which
non-destructively tests the conditions of the fluid or vapor by
determining the amount of light transmitted through the fluid or
vapor.
It is another object of the invention to provide a device which
non-destructively analyzes the composition of the fluid or vapor to
be tested by comparing the ratios of light of varying wave lengths
after it has been passed through the fluid to be tested.
It is a further object of the invention to alert the operator when
the ratio of the strength of light of varying wavelengths after
being passed through the fluid to be tested indicates that the
operating parameters of the fluid are outside a preselected range
of values.
It is another object of the invention to provide a device which may
be mounted in contact with the fluid to be tested to continuously
monitor the condition of the fluid.
It is yet another objective of the invention to provide a device
which is inexpensive to manufacture and simple to build.
These and other objectives of the invention will become clear from
the foregoing and from the following Detailed Description of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the invention.
FIG. 2A is a side view of the probe.
FIG. 2B is a plan view of the probe.
FIG. 3 is a block diagram of the electronics of the invention.
FIG. 4 is a block diagram of the preferred embodiment of the
signaling system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a block diagram of the invention generally labeled 10.
A probe 12 (FIG. 2A, B) is placed in contact with the fluid or
vapor to be tested. First and second light sources 14, 16, (FIG. 3)
respectively, each provide light of a preselected wavelength to
probe 12 through first and second input cables 24, 26 respectively.
Preferably, first and second light source 14, 16 are photo-diodes
while first and second input cable 24, 26 are fiber optic
cables.
In the preferred embodiment the photo-diodes are chosen to have
specific emission frequencies for the particular fuel to be
analyzed. These preselected wavelengths have been experimentally
determined to yield optimum results in determining the quality of
the fluid that is tested. Experience has shown that for most
fluids, the wavelength of light used ranges from 0.4 micrometers,
which is in the visible range, to 5 micrometers which is in the
mid-infrared range.
In analyzing ordinary motor oil, for example, it has been found
that wavelengths of 450 nm and 550 nm yield the most accurate
determination of the quality of the motor oil. Alternately, in
analyzing JP-10 jet fuel vapors, the fuel used in missile and
rocket propulsion, the wavelength of 1500 nm has been found to be
particularly effective.
Although photo diodes are the preferred light source 14,16 for the
instant invention, any other source of light which is able to
produce selected wavelengths such as standard LEDs, SRLEDs, or
laser diodes are within the scope of the invention. Additionally,
lasers at the preselected wavelengths, monochromatic incandescent
light sources, or filtered light which produces light at the
preselected wavelengths may also be used. These examples are merely
exemplary and not intended to be limiting. The important thing is
that light, including possibly modulated light, of preselected
wavelengths is made available. The preselected wavelengths may be
either fixed wavelengths or preselected bands of wavelengths which
may be scanned.
First and second input cables 24 26 are attached on their opposite
ends to probe 12 as shown in detail in FIG. 2A. Cables 24, 26 are
fiber optic cables. As can be seen, the first and second input
cables 24, 26, enter probe 12 through a connector 48. Connector 48
is in turn attached to bulk head 49. The fiber optic cables of
first and second input cables 24 and 26 extend through connector 48
and bulk head 49 and exit bulk head 49 through first and second
emission fibers 36, 46, respectively which are also fiber optic
cables.
Also extending out of the end of bulk head 49 are first and second
detection fibers 32, 42 also comprised of fiber optic cables. In
the preferred embodiment, each light source has its own fiber optic
cable carrying that light to and from the fluid reservoir. A first
and second gap 34, 44 separates the emission fibers 36, 46 and
detection fibers 32, 42 respectively. First and second gaps 34, 44
allow the fluid or vapor of interest to move between the respective
emission fibers 36, 46 and detection fibers 32, 42. Depending on
the fluid to be analyzed, the gap 34,44 between respective emission
and detection fibers 36,32 and 46,42 may be quite small, possibly
even being as small as a millimeter. Table 1 shows the length of
the gap 34, 44 found to be most effective in analyzing the
corresponding fluid or vapor with the respective wavelength of
light. Also shown is the type of analysis possible and whether the
analysis is qualitative or quantitative.
TABLE 1 ______________________________________ WAVE- LENGTH GAP
TYPE OF FLUID/VAPOR RANGE LENGTH ANALYSIS
______________________________________ Oil base lubricant 400-700
nm 1-20 mm Qualitative (fluid) Hydraulic Oil (fluid) 400-700 nm
1-20 mm Qualitative Brake fluid (fluid) 400-700 nm 1-20 mm
Qualitative Transmission fluid 400-700 nm 1-20 mm Qualitative
(fluid) Coolant or Radiator 400-700 nm 1-20 mm Qualitative (fluid)
Organic, Carbon 800-2000 nm 10-20 cm Quantitative based Fuel
(vapor) (Example-gasoline) Organic, Carbon 800-2000 nm 10-20 cm
Quantitative based Solvents (vapor)
______________________________________
First and second detection fibers 32, 42 extend through bulk head
49 and connector 48 to exit probe 12 through first and second
output cables 25, 27 respectively. Output cables 25, 27 are also
made of fiber optics, and are connected to spectrometer 18.
A screen 35 surrounds first and second emission fibers 36,46 and
first and second detection fibers 32,42. This screen 35 prevents
debris from entering first and second gaps 34,44 and disrupting the
light path between the respective emission and detection fibers. In
addition, a wall 37, shown in side view in FIG. 2A and in top view
in FIG. 2B, is placed between the respective pairs of emission and
detection fibers 36,32 and 46,42. This wall 37 prevents stray light
from one of the emission fibers 36,46 from being diffracted into
the other pair's detectors 42,32 and thereby affecting the light
signal detected across respective first and second gaps 34,44.
Spectrometer 18 comprises detectors 15, 17 and analyzes the
absolute strength or intensity of the light received from first and
second detection fibers 32, 34 which has been passed on to
spectrometer 18 through first and second output cables 25, 27.
Spectrometer 18 determines this absolute light strength for each
frequency of light received from the respective first and second
detection fibers 32,34. In essence, spectrometer 18 converts the
light signals of varying amplitude into a proportional electric
signal of varying electrical amplitude. Cadmium sulfide (CdS) or
Lead Sulfide/Lead Selenium (PbS/PbSe) detectors 15, 17 have been
found to be particularly adapted to perform this conversion.
Because two wavelengths of light are passed through the fluid to be
tested, and because the light of different frequencies interact
with the fluid differently, it is desirable to avoid having light
at one wavelength scattered through the fluid into the detector
corresponding to the other wavelength. This unwanted scattering is
avoided by alternately "pulsing" or activating the respective light
emitters 14,16 and simultaneously activating the corresponding
detectors 15, 17 within spectrometer 18. This "pulsing" is done by
modulator 28 which is a timer connected to a switch which
alternately activates and deactivates the respective light emitters
14, 16 and corresponding detectors 15, 17. An RCA-LM555CN timer and
GE-CD4066 Quad-Bilateral Switch have been found to produce an
excellent modulator 28. In this way, any scattered light of one
wavelength which may be received by the other wavelength's fiber
optic cables due to scattering through the fluid, impinges on an
inactive detector. Because the detectors 15, 17 is inactivated by
modulator 28, no "false" reading for the non-activated wavelength
is created. Additionally, the "pulsing" or modulation of the
emitters and detectors helps eliminate noise and drift, whether
electronically or environmentally induced, which has been found to
be present in long term, precision measurements.
After electrical signals corresponding in strength to the light
received by respective first and second detection fibers 32,34 has
been determined, the analog voltage signal produced by each
detector is filtered through filter 19 to improve the signal
quality. Filter 19 may be any analog or digital voltage filter
which suppresses spurious noise in the voltage signal from the
detectors. For example, filter 19 may include an A to D converter
followed by a digital filter followed in turn by a D to A
converter. As another example, filter 19 may include a phase locked
loop. Such filters are well known in the art. The resulting
filtered signal is now a "clean" signal free of spurious noise.
This "clean" signal may be amplified by amplifiers 23 A,B to
produce an appropriate signal strength as needed. The amplifiers 23
may be standard OP-AMPs. The outputs of amplifiers 23, A, B are
passed to Log converters 55A, B which determine the Log of each
wavelength's signal strength. Log converters 55A, B are diode
feedback type Log converters or Log/Antilog Amps such as GE-1CL8048
which are well known in the art.
The outputs from Log converters 55A, B are then divided by Analog
Divider 57 to produce a voltage based on the ratio of the outputs
of amplifiers 23A, B. This voltage is indicative of the fluid
quality. Analog divider 57 may be an analog divider/Multiplier such
as the Burr-Brown MPY100AG. This establishes the ratio of the
determined Logs according to the formula: ##EQU1##
In another embodiment, a central processing unit may be
appropriately connected to the outputs of amplifiers 23A, B to
calculate, according to preprogrammed instructions, the ratio of
voltages and produce a voltage or digital signal indicative of the
ratio.
In the preferred embodiment, and in the alternate embodiment where
a voltage representative of the ratio is produced, when the ratio
and consequently voltage moves outside of preselected values,
control signals are generated. The determination that the ratio is
outside the preselected values is done by a comparator stage
generally labeled 56. Comparator 56 may be a dual OP AMP or part of
as standard Quad OP AMP configured to operate in a window.
In the alternate embodiment containing a central processing unit,
the determination that the ratio is outside of the preselected
values and the generation of control signals may be done by the
central processing unit in response to preprogrammed
instructions.
These control signals in turn activate signaling mean 60 for
alerting the operator that the fluid has moved outside the range of
acceptable operating parameters. These signaling means 60 include,
in the preferred embodiment (FIG. 4), LED's 62, activated through a
multiplexer 64 connected to comparator 56, which visually indicate
that the fluid is outside the acceptable operating parameters.
Alternatively, or in addition, an audio alarm, or additional visual
alarm means such as flashing lights, as well as the possibility of
interacting with a computerized control system may also be
used.
In the preferred embodiment, bulk head 49 also includes threads 39
which allow probe 12 to be inserted into the wall of a container
containing a reservoir of the fluid or vapor to be tested. O-ring
38 is seated in bulk head 49 so that probe 12 will be in sealing
contact with the wall of the container containing the fluid or
vapor to be tested. Fiber optic input cables 24, 26 from the light
sources 14, 16 themselves may then be attached to the appropriate
fiber optic cables of the probe 12, or the light sources 14, 16 may
themselves be attached to the ends of fiber optic cables of the
probe 12.
Also in the preferred embodiment, a power supply 66 (FIG. 4) is
provided which is connected to an alternating current source 68
such as a wall socket. Power supply 66 converts alternating current
to direct current for powering the electronic components of the
device 10 by means well known in the art.
In an alternate embodiment, a handle may be attached to bulkhead 49
to allow for manual placement of the probe 12 directly into a fluid
or vapor to be tested. This embodiment of the invention will be
particularly suited for testing samples of fluid in a spot-check
fashion. In this embodiment, the spectrometer 18, filter 19, log
converters 55, comparator 56, analog divider 57 and signaling means
60, as well as first and second light source 14, 16 may all be
contained in a single portable unit which is connected to probe 12
by first and second input and output cables 24, 26 and 25, 27,
respectively. In this embodiment, power supply 66 is preferably a
battery to render the device 10 more portable. However, the power
supply of the preferred embodiment may also be used in this
embodiment.
While the instant invention has been described in relation to
fluids, it works equally well when addressed to the analysis of
vapors. When used in this context, vapors instead of fluid is
present in the gap 34,44 between the fiber optic cables.
While the instant invention has been described in what is
considered to be the preferred embodiment, as well as alternative
embodiments, it is to be understood that these descriptions are
given by means of example only, and not by means of limitation. It
is to be understood that changes and modifications may be made to
the description given and still be within the scope of the
invention. Further, it is clear that obvious changes and
modifications will occur to those skilled in the art.
* * * * *